A power transmission device in which a speed change device is coupled with an engine via a travel clutch is known from, for example, Japanese Patent Application Laid-Open Publication No. 63-223207 (JP 63-223207 A).
As disclosed in JP 63-223207 A, a drive pulley is attached to the output shaft of an engine mounted in a small-sized snow remover, a driven pulley is attached to the input shaft of the speed change device, and an endless V belt is trained around the drive pulley and the driven pulley.
A travel clutch is provided beside the V belt in order to engage and disengage the power transmitted to the speed change device from the engine. The travel clutch is provided with a roller capable of pushing against the V belt.
The endless V belt is trained around the drive pulley and the driven pulley in a slackened state. In this state, power is not transmitted to the input shaft of the speed change device from the output shaft of the engine, but when the roller presses against the endless V belt, the endless V belt tightens, and power is transmitted from the drive pulley to the driven pulley.
In the speed change device, the meshing of speed change gears is switched by operating a shift lever to allow forward, reverse, and neutral modes to be selected. When a mode other than neutral is selected, the meshing of a predetermined speed change gear and connection of the travel clutch occur simultaneously in conjunction with the operation of the shift lever.
In the small-sized snow remover disclosed in Japanese Laid-open Patent Publication No. 63-223207, there is a need particularly for cost reduction, a speed change device provided with a plurality of gears in which high-precision components are required is difficult to employ, and a speed change device having a simple structure is needed. For example, the mechanism for switching between forward and reverse travel in the speed change device is preferably simple, but the ability to smoothly switch between forward and reverse is also necessary. Cost can also be further reduced if the travel clutch similarly has a simple structure.
There are also instances in which the small-sized snow remover is pushed or pulled, or moved in different directions by hand without the aid of the drive power of the small-sized snow remover according to conditions in the location where snow is removed, for example. The ability to set/maintain the neutral state of the speed change device by a simple structure is needed for the sake of convenience, so that the small-sized snow remover can be made to change direction or move merely by human power.
A forward-reverse switching lever provided to a steering handle is known as a forward-reverse switch operating mechanism, as disclosed in Japanese Patent Application Laid-Open Publication No. 2001-271926 (JP 2001-271926 A).
According to the forward-reverse switch operating mechanism disclosed in JP 2001-271926 A, a forward-reverse switching lever for switching the forward and reverse travel of a binder is provided to the steering handle of a binder.
This forward-reverse switching lever is normally held in an upright position, and forward travel is achieved by pushing the lever forward from the upright position, and reverse travel is achieved by pushing the lever backward from the upright position.
Since a locking mechanism for retaining the lever in the forward or reverse position is not provided to the forward-reverse switching lever described above, the operator must directly maintain the forward-reverse switching lever in the forward position or the reverse position by hand while the binder is traveling forward or backward.
Particularly when the lever is in the forward position, the operator must maintain a posture in which the hand is extended a long distance forward, and this places a significant burden on the operator. There is a need to reduce the retaining force if possible, and such an enhancement is also needed for operability.
Furthermore, the structure for coupling the forward-reverse switching lever and two operating cables together is complex, and the cost involved creates a need for a simplified structure.
Furthermore, when the forward-reverse switching lever is in the forward position or the reverse position, one of the operating cables is in a slackened state, and can interfere with operation.